Carbonisation of solid fuels



NOV, 4, 1969 1 P. l.. v. LEDENT v 3,476,649

CARBONISATIN OF SOLID FUELS IIIlIII. Illllull Filed April 9. 1965 #f-PP;fa/v wcm@ dy M J. da@

United States Patent O U.S. Cl. 201-12 2 Claims ABSTRACT F THEDISCLOSURE A method and device for the carbonisation of briquettes orpieces of solid fuel by j treatment in a bed of granulated material usedas thermofor, uidised intermittently and which ows by gravity in auidised channel that is at a slight slope, comprising distributing thematerial used as thermofor in two fractions, one of which is introducedas the entry of the treatment channel simultaneously with the productsto be treated, the other being added progressively at a plurality ofstations into the mid-part of the treatment channel so as to reheat themixture.

The invention has for its object improvements in methods and apparatusfor the carbonisation of solid fuels in the form of briquettes, orpieces.

It is known that briquettes or pieces of coal or other solid fuels canbe treated in a bed of sand or other granulated material used asthermofor, fluidised continuously or intermittently and which flows bygravity from one end to the other of a horizontal treatment channel orone that i-s inclined at a slight slope, wherein the speed ofuidisation, the granulometry and the specific weight of the thermoforare regulated in such a way that the apparent density of the uidised bedis a little greater than the density of the products to be treated.

It is also known that the fluidisation of the treatment channel, can becarried out intermittently, by altemating very short periods ofiluidisation with relatively long periods of stationary bed.

In the said methods all the hot sand used as thermofor is introduced atthe entry to the treatment channel, simultaneously with the products tobe treated.

Experiments have been carried out and have shown that to avoid a tooabrupt thermal shock which might damage the products to be treated, itwas advantageous to fractionate the introduction of the thermofor.

In the process in accordance with the invention the rate of flow of hotsand or other material used as thermofor is distributed in twofractions; the first fraction is introduced at the entry of thetreatment channel simultaneously with the products to be treated; thetemperature and the rate of flow of the said first fraction areregulated in such a way that after 15 to 20 minutes of mixing, thetemperature of the mixture thermofor|prod ucts is between 440 C. and 480C. The second fraction is added progressively in the mid-part of thetreatment channel, so as to reheat the mixture, the temperature and therate of flow of the said second fraction being regulated in such a waythat at the outlet of the treatment channel, the temperature of themixture thermofor-l-products is between 500 C. and 600 C.

When the said method is used for the treatment of briquettes of grams,the total carbonisation time is between 50 and 75 minutes.

By way of example there are given below the results rice obtained by theprogressive carbonisation of a type of -briquette of approximately 20grams:

Composition: Percent Coking coal (at 25% VM) 94 Lignosulphite in powderform 1 Sulphur l Conditions of treatment:

Total duration minutes-- 60 Initial temperature of the sand C..- 1-650Temperature after mixture of the first fraction C-- 470 Finaltemperature of the mixture sand-l-briquettes C-.. 530

Characteristics of the briquettes:

Specific weight g./cm.3 0.88 Resistance to compression k1os 117 Volatilematter (dry basis) percent-- 10.1

The present invention also concerns apparatus adapted to carry out thesaid method of carbonisation and, for carbonisation by treatment in albed of sand or other material used as thermofor, lluidisedintermittently and flowing by gravity in a horizontal channel, or onethat is inclined at a slight slope, said apparatus has the feature thatthe heating chamber of the thermofor is connected to the treatmentchannel by two channels distributing the thermofor, provided with meansfor regulating the ow, one of which at the entry of the treatmentchannel and the other feeds a elevated distribution channel carried outin the form of an air slide and having a series of ow orices which makeit possible to distribute the thermofor in the mid-part of the treatmentchannel.

The invention will now be described solely by way of example and in norestrictive sense, by means of the attached drawings, which shown anapparatus or furnace for carrying out the method of carbonisation of theinvention.

FIG-UIRE 1 shows a plane view in diagrammatic form of the treatmentfurnace.

FIGURE 2 shows a diagrammatic section along the line 2 2 of FIGURE 1.

Referring to the drawing, the main members of the furnace are asfollows: entry sluice 1, treatment channel 2, outlet sluice 3, sieve 4,heating chamber for the sand used as thermofor 5, lifting device i.e.air lift for the sand 6, distribution for the lirst fraction of hot sand7, distribution channel for the second fraction of hot sand 8.

A furnace of this type, in which the entry and outlet sluices 1 and 3respectively are lseparated from the treatment channel 2 by partitionsdipping down under the level of the sand in such a way as to form atrap, has the feature that there are two distribution channels for thehot sand or other thermofor, provided with means for regulating the rateof ow, i.e. the channels 7 and 8 respectively, the channel 7 connectingthe heating chamber of the sand 5 to the entry of the treatment channel2, and the channel 8 in connection with the said heating chamber andforming the elevated distribution channel, carried out in the form of anair slide and having a series of orifices 8', which make it possible todistribute the second fraction of the llow of sand into the mid-part ofthe treatment channel 2, as can 'be seen in the drawing.

What I claim is:

1. A method for the carbonization of briquettes or pieces of` solid fuelby treatment in a bed of granulated material used as thermofor,fluidized intermittently and which ilows by gravity in a iluidizedchannel that is at a slight slope, comprising directing the materialused as thermofor in two parallel paths, one of the paths introduced atthe entry of the treatment channel simultaneously with the products tobe treated, the other path being added progressively at a plurality ofstations into the mid-part of the treatment channel so as to reheat themixture, the plurality of stations extending longitudinally of theiluidized channel.

2. The method of claim 4, further comprising regulating the temperatureof the thermofor and the rate of ow in each of the two parallel paths insuch a way that the temperature of the mixture products to be.treated-l-rst path is between 440 C. and 480 C. and the nal temperatureof the products to be treated-Hirst path-l-second path is between 500 C.and 600 C.

References Cited UNITED STATES PATENTS 2,638,219 1/1951 Welty 201-31 XRFOREIGN PATENTS 5/1951 Belgium.

10 NORMAN YUDKOFF, Primary Examiner D. EDWARDS, A-ssistant Examiner U.S.Cl. X.R.

